CVE-2026-25637
📋 TL;DR
A memory leak vulnerability in ImageMagick's ASHLAR image writer allows attackers to cause denial of service by exhausting process memory through crafted images. This affects all systems running vulnerable versions of ImageMagick that process untrusted image files. The vulnerability is particularly relevant for web applications and services that use ImageMagick for image processing.
💻 Affected Systems
- ImageMagick
- Magick.NET
- Any software using ImageMagick library
📦 What is this software?
Imagemagick by Imagemagick
Magick.net by Dlemstra
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service causing application crashes, service unavailability, and potential system instability due to memory exhaustion.
Likely Case
Degraded performance, intermittent crashes, and resource exhaustion affecting image processing functionality.
If Mitigated
Minimal impact with proper input validation, resource limits, and isolation of image processing components.
🎯 Exploit Status
Exploitation requires crafting specific ASHLAR format images. No public exploit code has been observed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 7.1.2-15
Vendor Advisory: https://github.com/ImageMagick/ImageMagick/security/advisories/GHSA-gm37-qx7w-p258
Restart Required: Yes
Instructions:
1. Update ImageMagick to version 7.1.2-15 or later. 2. For Magick.NET, update to version 14.10.3 or later. 3. Restart all services using ImageMagick.
🔧 Temporary Workarounds
Disable ASHLAR format processing
allRemove or disable ASHLAR format support in ImageMagick policy.xml
Edit /etc/ImageMagick-7/policy.xml or equivalent
Add: <policy domain="coder" rights="none" pattern="ASHLAR" />
Implement resource limits
linuxSet memory and resource limits for ImageMagick processes
ulimit -v 1048576
Set memory limits in container/pod configurations
🧯 If You Can't Patch
- Implement strict input validation to reject suspicious or malformed image files
- Isolate image processing to dedicated containers/instances with resource limits
🔍 How to Verify
Check if Vulnerable:
Check ImageMagick version with: convert --version | grep VersionCheck Version:
convert --version | grep VersionVerify Fix Applied:
Verify version is 7.1.2-15 or later: convert --version | grep 'Version: ImageMagick 7.1.2-15'📡 Detection & Monitoring
Log Indicators:
- Memory allocation failures
- Process crashes with out-of-memory errors
- High memory usage by ImageMagick processes
Network Indicators:
- Unusual image upload patterns
- Multiple failed image processing requests
SIEM Query:
process.name:"convert" AND (memory.usage > 90% OR exit_code:137)